Electric phonograph



Sept. 30, 1930. l A. A. THoMA's 1,775,987.

ELECTRI C PHONOGHAPH pt 30, 1930. A'. A. THOMAS ELECTRIC PHONOGRAPH '5Sheets-Sheet 2 Filed Oct. 8, 1926 Sept. 30, 1930. A. A. THOMAS y1,776,987

' ELECTRIC PHONOGRAPH Filed oct. 8, 192e s sheets-sheen V:i

JrM N l Patented 30, 1930 electric phonographof .novel constructionswinging doors which, when UNITED STATES' ADOLPH A. THOMAS,

PTENT OFI-Ica OF NEW YORK, N. Y.i

ELECTRIC PHoNoGaAPH Application med october s,

1926." serial No. Masts.

. My invention relates to sound-reproduc :the doorsare'swung'opemaswitch controlling ing'machines, and its object is toprovide an and improved operation. The various features of-m inventionare particularly'adapted to pro uce an electric phonograph of the smallportable type and yet capable of giving a loud reproduction equal inquality and volume to that of large cabinet machines.

The electric phonograph of my invention uses no amplifying horn, but alarge loudspeaking diaphragm is mounted in horizontal position below themotor board of the outer casing, which need not be much larger than thediaphragm itself. Aninside artition divides the'ase or box of the maciney into upper and lower compartments. In'the lower compartment is thediaphragm, and the upper compartment houses the various electricaldevices of the reproducing'circuits, such as batteries,transformers,resistances, vacuum tubes7 and so forth. vOn-the motorhoard are conveniently mounted -certain control members by whicli thevolume of reproduction may be vregulated as desired. The diaphragmcompartment has one or twof open; allow the vibrations of' hediaphragm'to ass-into the" free air allaround. ,v By adjusting theosition of the doors', the'sound waves are de e'cted into thedesireddirection. The relative.-

arrangement of thediaphragm and the parti tion above it is such thatsound waves striking the partition are thrown out ofthe casing,l

. so that the full acoustic effect ofithe :dia-.j

phragm is impressed upon th'e' outer air." By

the filament circuits automatically closes.' As a further precautionagainst wasting filament and plate current, I provide an additional?switch device which closes the filament circuits only when theamplifying circuit of the electromagnetic "Lmechanism "for the diaphragm is completed. In-the circuit connections .for electricallytransmitting the`needle` vibrations to thediaphra'grm' I mayuse one ormore amplifying tubes. A two-stage ain-- plification is ordinarilysuicient, andiI provide novelafeontrol means for using one or' morestai'g'e's of amplification by sim ly moving a finger piece onthemotorboar When tlus finger piece is in neutral position, all4 batterycircuits are open. All the electrical parts that com rise the amplifyingsystem are preferably y oused in separate chambers formed in the spacebetween the motor-board and the transverse partition previouslymentioned. These chambers are closedby covers' mounted on themotor-board and easily moved'l into openA positions The various featuresand advantages of' my invention will be fully understood from adetailedL description of the accompanying drawings,- which illustrate aportable electric honograph'embodying my invention. 'Beore proceeding Iwant to make it clear that1 using a diaphragm of sufficient size, it ispos- 'Y- imately on line 1-1 of Fig. 2

Fig. 2 represents a planview of the masible to obtain tremendousvolume-from aA small portable machine. The lid of the caseis'co'nstructed to support a number of records, which do not Ainterferewith thel mechanism above'the turntable when the lid is closed.

Referringto the electrical features of my newl phonograph, I may brieflymention at!` this point the Vautomatic control ofthe reproducer circuitsto prevent waste ofi current when the machine isnotin playing condition.As long as the -doors of the diaphragm-A compartment are closed, thefilament circuitsand'the doors swung open; and

.iiIl the amplifying tubes remain open:' When Fig. 7 illustratesdiagrammatically the cir 85'; Fig. 1 is a transverse cross-sectionapprox panel 14 a continuous cylindrical Wall, which cuit connections ofthe reproducing system for electrically transmitting the needlevibrations to the loudspeaking diaphragm.

The outer case or cabinet of the phonograph is here shown as acylindrical box suitable for carrying and adapted to be completelyclosed, like a piece of hand baggage.- In its general construction, this'box or case consists of a body part 10, a base or bottom 11, and a lid12 for closing the top. A suitable lock holds the lid closed when thecase is carried about. The base 11 is rigidly connected with thecylindrical section 10 by posts 13 and a rear panel 14. -At the ends ofpanel 14 are hinged two doors 15 and 16, the hinge Connections beingindicated at 17. These doors are so made that when closed they form withthe constitutes a part of the closed outer casing. The free ends of thedoors abut against the front post 13, and suitable means may be providedfor locking the doors or yieldably holding them in closed position. InFig. 6 I have shown spring-pressed buttons 18 mounted on the base andadapted to enter recesses in the bottom of the doors.

The body-section 10 of the cabinet is provided at the top with amotor-board 19 securely held in place by any practical means, as b anannular ledge or shoulder 20. Within the cabinet is fixed a transversepartition 21, which is here .shown as a conical disk with? thev apexpointing downwardly.- The disk 21 thus divides the casing into an uppercompartment 22 and a lower compartment v23 (see' Figs. 1 and 3), whichare acoustically separated from each other, or practically' so. A ring24 fixed to the body section 10 holds the-disk 21 in place, or any otherfastening -means may be used.

Over the top board 19 is mounted a turntable 25 carried on a rotaryl'shaft 26, which is driven by a suitable mot-or 27, fastened to theunderside` of the turntable in the usual way.

This motor maybe electrical or mechanical, and it will not -be necessaryto show any details of its construction. So I have merely indicated thedriving motor diagrammatb cally by the outline 27. A stand or post 28,fixed on the top board 19 at the proper place, has pivoted thereon anarm 29 carrying an electric reproducer 30 of any approved type diaphraor design. As/ there are several makes of electric phonographreproducers on the market, I need not encumber the description anddrawings with details of the interior machanism of reproducer 30. It issuicient to say here that the needle vibrations operatev the reproducerto ,generate current impulses which are amplifie to operate a-louds akeras will later be explaine more fully. he arm 29 is so pivoted on stand28 as to swin horizontally over a record 31 on the'turnta le and also'to move in a vertical direction when necessary.

In the lower compartment 23 of the outer casing is mounted aloudspeaking diaphragm 32, secured at its circumference to the base 11in any practical Way, as by a clamping ring 33 suitably fastened to thebase. When this ring is secured in position, it becomes part of the baseand art of the outer casing, as may be seen'in ig. 4. In assembling theparts of the particular construction which I am describing as an exampleof my invention, the diaphragm 32 and ring 33 are attached to the basebefore the latter is secured to the posts 13. Thedotted line 34 in Fig.6 indicates the circumferential edge of diaphragm 32, which is mostconveniently (but not essentially) made in conical form,

like the diaphragms of the various cone suitable for the purpose. In thespace be-y tween the center of diaphragm 32 and base 11 is mounted anelectro-magnetic unit 35 for actuating the diaphragm. As there are manytypes of such driving units on the market, I need not show or describeany details of unit 35, except to say that a link or rod 36 is connectedat one end to the center oil diaphragm 32 andyat the other end to thevibratory member of the driving unit. The connection 36 may bedispensedwith Iby providing the diaphragm W1th an armature arranged inoperative relation to the magnetic poles of .the driving mechanism.Instead of mounting unit 35 on base 11, it may be sccured to thepartition 21 in compartment 22.

The partition 21 and diaphragm 32 have small holes 37 for the passage ofconductors 38 and 39, which connect the coil or coils of driving unit 35in the amplifying circuits, as vpresently Willbe described. The holes 37are just-big enough to accommodate the wires, whichA are so light andflexible as not to interferejwith the vibrations of the diaphragm.`

insulating material.-

Referring to Figs. 1 and 3, it will be seen that the conical disk orartition 21 acts as a sound deflector :for the to throw the soundv wavesout of .the cabinet in all directions. By making this deilector ofAresonant material like a sounding board, the vibrations of thediaphragm are stren hened.V Thel rear panel 14 serves to de ect soundforwardly, and the doors 15 and 16 41, which hold the bottom of thecabinet raised. These lugs are preferably of soundaphragm and tends maybe adjusted at the pr oper angle to conthe desired direction.

In the upper compartment 22 of thev cabi- `net are housed all the partsand wiringthat go to make up the electric amplifying system between thereproducer and the drivingunit 35. The number of these parts will ob`-viously depend upon the particular amplifyf ing system used. In thepresent instance, I

have shown a two-stage system with means for cutting out one stage ifdesired. This requires two amplifying tubes, two transformers, filamentand plate batteries, and certain switch mechanism. All these parts aresuitably mounted in the space between the motorboard 19 and partition21. At the present time I prefer to'provide separate chambers orrecesses for the transformers and batteries, so that ready access may behad to each part without removing or lifting the motor-board. Figs. 1, 2and .3 show four of these separate chambers, as indicated by referencenumerals 42, 43, 44 and 45.. yThese chambers, which are really small'boxes or frameworks, may'conveniently be formed out of sheet metal orother material and secured to motor-board 19 so as to hang incompartment 22. The board 19 is cut out to leave the top of each box orchamber o en. A cover 46 is provided for each box, hese covers may bestamped from sheet metal and are slidably mounted be tween parallelguide strips 47 fastened to the motor-board, as best shown in Figs. 2and 5. A linger piece 48` at the outer edge of each cover permits easymanipulation of the same into open and closed positions. Figs. 1 and 2show'one of the covers pushed open.

Inchamber 42 is mounted a transformer 49 of suitable construction notnecessary to describe. A spring clamp 50 holds the transformer securelyin proper position without the need of additional fastening means.l Afurther advantage of spring clamp`50 lies in the fact that it permitsready removal and insertion of 'the transformer by hand, no tools beingrequired. In the present instance, the transformer has four insulatedterminals 52 whichare pressed by spring clamp 50 against four insulatedcontacts 53 mounted on a wall of chamber 42. Therefore, the mereinsertion of transformer 49 into the chamber'automatically connectstheprimary andsecondary Cil coils of the transformer in the amplifyingsystem about to be described. A similar transformer 54 is mounted inchamber 45,'and what has been said aboveon themounting and connectionsof transformer 49 ap lies to transformer A54 without the need orepetitio'n. v Y

In chamber 43 is housed a cell or battery 55, (which may be regarded asthe filament or so-called, A battery. A pair of spring members 56carriedby the box or framework 43 hold the battery in fixed position and yetallow the same to be easily removed when desired. Conductors 57 are ledinto the chamber through la small hole and attached to the batteryterminals 58.

A plate or B battery is supported in chamber 44, but it will not benecessary'to show it, for what has been said about the mounting of the Abattery 55 applies to the plate battery, which is indicated dia.-grammatically at 59 in Fig..7.

Two amplifying tubes 60 and 61 are mounted on a suitable support 62 inthe forward v i part of compartment 22. The structural details ofsupport 62 need not be shown or described, for the mounting of vacuumtubes in sockets is well known. The tubes 60 and 61 are of the usualthree-electrodetype suitable for amplifying current impulses. Themotor-board 19 has openings 63 through which the tubes project suciently to be grasped by the fingers for removal. Also, the openings 63permit the insertion of new tubes without lifting the board 19. Toprevent vibration of the tubes, I fasten yieldable rings 64 to theunderside of the motor-board around the openings 63. The rings 64 aremade of felt, rubber, leather, 0r other suit' tween the tubes 6() and 61to let the operator fknow that the filament circuit-is on or ofi'. Asocket 66 (see Fig. 4) is fixed on tube support 62 for receiving thesignal lamp 65. This lamp 'mayof course,fbe supported in any other psition where it is readily visible.

On the front postl 13 in compartment 23 is mounted a suitable. switch67, here shown for convenience in the form of two insulated springcontacts which are normally held closed by their own inherent tension.One of the doors (for example, 'door 15) carries an insulated wedge 68arranged to enter between the switch contacts 67 and hold them apart`when the door is closed, as may be seen in Fig. 4. When the door 15 isopened, the contacts 67 automatically snap together and vclose thecircuit of filament battery 55 as. will be better understood when I cometo describe the circuit connections of Fig. 7. Therefore, as long asthe'door 15 or 16) remains closed, theilament'circuit is open and nowaste of current is possible. It is obvious that switch 67 may be soarranged as to require the opening of both doorsto'close the switch andthe closing of either door to open the switch. For 'this it is onlynecessary to have two pairs of' ly representative of suitable switchmeans controlled by one or both doorsof the cabinet.

Looking at Figs. 2 and 3, there is a finger piece 69 in the shape of asmall knob projecting. through an arcuate slot 70 in the top board 19.This finger piece controls certain switch mechanism indicated as a wholeby W, which I shall now describe, reference being had to Fig. 7 wherethis mechanism is shown as simply as possible in a diagrammatic way.

rlhe knob 69 is fixed to a link 71 of insulating.

material, which is connected to a air of arms 72 and 73 pivoted atpoints 7 4 aniil 7 5, respectively. In practice, these arms may consistof insulating bars pivoted to the underside of the motor-board andcarrying contact pieces 76, 77, 78 and 79, as indicated. The two contactpieces on each arm are electrically insulated from each other. With theswitch arm 72 are associated two pairs of fixed contacts or terminals80-81 and 82-83. These terminals are so arranged that in one position ofarm 72 the contact pieces 76 and 77 engage terminals 80 and 81,respectively, 'while in the other position of arm 7 2 the same contactpieces engage terminals 82 and 83, respectively. The other switch arm 73has associated therewith two pairs of fixed contacts or terminals 841-85and 86-87. When switch arm 72 touches the terminals 80 and 81, as justdescribed, the switch arm 73 `1s 1n contact with terminals 84 and 85.This i s the position of the switch arms shown in Flg. 7. When theswitch arm 72 touches the other pair of terminals 82 and 83, the switcharm 3 engages terminals 86 and 87. I have pur' posely omitted to showthe second position of the switch arms in Fig. 7 so as not to createconfusion by the crossing of lines.

Now for the circuit connections in Fig. 7. One side of the reproducercircuit is connected by a Wire 88 to the grid 89 of tube 60, and theother side of that circuit is completed through the filament 90 andconnections 91 and 92. The operation of reproducer 30 causes variablevoltages to be impressed on grid 89, as will be understood withoutfurther explanation. The plate electrode 93 of tube 60 is connected by awire 94 to one terminal of the primary coil 95 of transformer 49, andthe other side of that coil is connected through wire 96 to the positiveterminal 97 of plate battery A rheostat 98 having a controlling arm 99is `preferably insertediin the plate circuit to regulate the normalcurrent and potential values. The rlieostat is supported beneaththe'motor-board and the rheostat arm `99 1s operated by aknob 100 on themotor-board, as shown in Fig. 2. As the knob'100 is turned to the right,the resistance 99 is gradually cut out and the ultimate effect 1s toincrease the volume of reproductlon and also to obtain the desiredquallty 1n the amplified reproduction. Different tubes may requiredifferent plate currents for the best acoustic results ina giveninstrument.

The primary coil 101 of transformer 54 is connected at one side to theplate electrode 102 of tube 61, and the other side of the coil isconnected by Wire 103 to the positive terminal of battery 59. -Aconductor 104 connects the nega-tive side of battery 59 to the filament90 of tube 60, and a conductor 105 connects the filament 106 of tube 61with the same side of 'the battery. In other Words, the primary coils 95and 101 (and therefore the plate circuits of the amplifying tubes) areconnected in parallel to battery 59. The rheostat 98 is so arranged asto control the two plate circuits simultaneously when both tubes areworking.

One sidel of filament 90 is'connected to one pole of battery 55 througha wire 107 and switch 67. The other side of filament 90 is connected toa wire 108, and the other pole of battery 55 is connected to a Wire 109through the signal lamp and a rheostat 110 suit.- ably supported beneaththe topboard 19. The lamp 65 and rheostat 110 are connected in series.To prevent interruption of the filament circuit (or circuits') Iin theevent that the signal lamp 65 is out of commissi'omI shunt the lamp witha resistance 111, which oughtto be of about the same ,value as theresistance of the lamp. This resistance may be mounted on tube support62. 'The rheo'- stat arm 112 is operated by a knob 113, or other fingerpiece, on. the motor-board 19 (see Fig. 2). The cdnductor 108 has twobranches 114 and 115, which are permanently connected, respectively, toinsulated contact pieces 116 and 117 carried by the pivoted switch arms72 and 73. Conductor 109 of the filament circuit is permanentlyconnected toa pair of fixed terminals 118 and 119. When the switch arm72 engages contacts 80 and 81, the contact piece 116 engages terminal-118; when the switch arm is thrown over to l make contact with terminals82 and 83, the contact piece 116 engages terminal 119. Thus, in eitheroperative position of the switch arm, the circuit of filament 90 isclosed. But when the switch arm 72 is in a neutral position-'that is,out of engagement with both pairs of contacts 80-8'1 and 82-83, thecontact member 116 does not engage either of the terminals 118 and 119,so that the filament circuit is open, even if switch 67 should beclosed.

The circuit of filament 106 includes a conductor 120 for connecting oneside ofthe filament with battery 55, and a conductor`121 which ispermanently connected to a fixed contact or terminal122. When the switcharm 73 is in the position shown in Fi 7 thecontact 122 is isolated andthe circult of filament 106 is open. When the switch arm 73 is thrownover to engage the terminals 86 gages the terminal '122 and therebylclosesl the filament circuit of tube 61. This means l that both-tubesare. in operation, with the filament circuits connected in parallel.

The ends of the secondary coil 123 oftransformer 49 are permanentlyconnected to the contact parts 76 and 7 7v of switch arm 72 by wires 124and 125. The ends of the secondary coil 126 of transformer 54 arepermanently connected to the switch contacts 86-and 87 by conductors 127and 128. The switch contacts 80 and 84 are connected by a wire 129, and

' switch contacts 81 and 85 are connected by a wire 130. Switchterminal82 is connected by a wire`131 to the grid 132 of tube61. Thefixed contact 83v is connected by a wire 133 to the conductor'105, whichleads from the fila-- ment 106. The conductors 3,8 and 39 of theelectromagnetic driving unit are connected, respectively, vto thecontact parts 7 Sand 79 of switcharm 73.

. I may insert here, in passing, that when 'I refer to an electricconnection as awire, I use the word as a convenient way to include anypractical form of electrical connector, whether it be a wire, rodpla'te,or what not.

The operation of the amplifying systemdisclose'd in Fig. 7 is thefollowing: Assuming switch 67'closed and switch mechanism W in theposition illustrated, the plate circuit of tube is traced from theositive terminal 97 of battery 59, through r eostat 98 and I therethrough wire 109, rheostat 110 and signal lamp (alsothrough resistance111 if present) to the other side of battery 55. The

circuit of the secondaryl coil 123 follows this path: from one end ofthe coil through wire 124 to contact member 76 of switch arm 72,

through wire 129 to switch terminal 84, from there through lead 38 tothe electromagnetic mechanism of unit 35, through the return lead 39 tocontact part 79, through wire 130 to switch terminal 81, then throughcontact part 77 and wire 125 backto the coil.

1t will be clear from the preceding description that, 4when the switchmechanism Wis in the position illustrated in'Fig. 7, the secondamplifying tube 61 is entirely cut out and the diaphragm'32 operates ona single stage of amplification. This fact is indicated to the o eratorby the one position of controlling `nolo 69, as shown inFig. 2. Toobtain a two-stage amplification, the operator moves knob 69 over to theother end of slot 70 into the two position, as indicated by a dottedcircle 69 in Fig. 2. This movement of knob 69 rocks the swltch arms 72and 73 into contact with the other pairs of terminals 82-83 and 8687, aspreviously explained. Both tubes are now in operation. .The filamentcircuit of tube 60 is traced as before, except that from contact piece116 we now go to terminal 119. The lament circuit of tube 61 is from oneside of battery 55 through wire 120 to filament 106, from therethroughwire 121 to V terminal 122, which is now engaged by contact piece 117,from there through wires 115 and 114 to contact piece 116, and then hometo battery 55 through the path already traced for filament 9.0. The twofilament circuits are therefore connected in parallel with battery 55.The plate circuit of tube 60 is the same as before. The plate circuit oftube 61 is from the'l ositive side 97 of battery 59 through con uctor103, through primary coil 101 to plate electrode 102, across theelectronic path in tube 61 to one side of filament 106, and'throughconductor 105 back to the battery. It is clear from this that the platecircuits, and'therefore the circuits of the primary coils 95- and 101,are connected in parallel when both tubes are in operation. The circuitof' secondary coil 123 is completed thus: from one end of the coil towire 124 and contact part 76, which now touches the terminal 82, throughconnection 131 to grid 132 of tube 61, through one side of filament 106,through conductors 105 and 133 to switch terminal 83 which is now enaged by contact member 77 of switch arm .72, then through wire 125 backhome to coil 123. The circuit last traced is the rid circuit of tube 61,and the electric im u ses in this circuit produce greatly ampli edcurrent im ulses in the circuit of primary coil 101. he circuit ofsecondary coil 126, when the contact members 78 and 79 engage the switchterminals 86 and 87, respectively, passes through the operating coil orcoils of the driving unit '35 'by means of connections 38 and 39 asalready mentioned.

.Vl/'hen the knob 69 is moved to an inter- 1n other` words, theoiposition of knob 69 assures the operator that all circuit con-Anections are open and no battery current is beingbneedlessly consumed.Suitable means may eprovided to hold the switch arms in actuatedposition, so as to obviate the risk of accidental dis lacement when'tliephonograph is carrie about orotherwise unexpectedly jarred. As a1practical example of such retaining means, have s hown in Fig. 7 aspring member 134 comprising a corrugated strip or wire secured at'itsends 135.

This strip or wire has as many corrugations 'or recesses 136 as thereare positions of thev switch arms 72 and 73. The link 71 carries a cam137 adapted to enter the recesses in s ring member 134, which pressesagainst the cam enough to hold the switch in actuated position. Thespring member 134 is sufficiently yielding to permit movement of theswitch arms 72 and 73 from one position to the other by a slightpressure on knob 69.

I have purposely shown the. lid 12 of the cabinet deeper than actuallynecessary, so as to show how a stack of records 138 may be attached tothe inside of the lid. For this purpose the lid carries a screw rod 139on which the records are strung and clamped in place by a wing nut 140.A washer or small disk 141 is preferably interposed to prevent injury tothe records when the nut is screwed home. In Fig. 1, the dotted outline42 indicates the depth of a stack of records that may be carried in thecabinet without interfering with the closing of the lid. The rod 139 is,of course, made long enough to lhold the desired number of records. thepresent embodiment I have the turntable 25 to be ten inches in diameter,but the machine operates equally well on 12-inch records, and theselarge records can be supported in the lid without interference by thereproducer arm 29. The record 31 shown in Fig. 2 is supposed to be a10-inch record, and a 12-inch record extends to the dotted circle 142,which is clear of reproducer arm 29 when the latter is in idle or restposition. To insure this position of arm 29 before the lid is closed, Iprovide a rest 143 on the motorboard adapted to engage the reproducerarm and hold it until released. In the present instance, the rest 143terminates in a pair of spring fingers 144, between which the arm 29 isheld clamped without danger of displacement during transportation of themachine. An other practical means may be used to hol the reproducer armin fixed posi- 1tinout of the way of the records in the A handle 146 isfixed to the body section 10 of the cabinet in such position that themachine as a whole feels pretty well balanced when held by the handle.When the outer box of themachi'ne is made circular. as herein shown, Iprovide a foot piece 147 opposite the handle to act as a standorsupporting base for the box in upright position. The straight edge ofthis foot piece affords the additional advantage of permitting the useof a long substantial hinge 148 for the lid 12.

Attention is called to the symmetrical arrangement'of the batteries andtransformers in compartment 22, so as to obtain a substantially balanceddistribution of the Weight o' those parts on either side of the carryinghandle. This is clear from Fig. 2. The batteries, which are the:heaviest parts in the In b -chamber necessary to accommodate thedownwardly extending board 21 and the upwardly pointing diaphragm 32,and also with the depth of lid 12 to accommodate a certain number ofrecords. An 18-inch diaphragm, properly constructed and operated, willgive 'a reproduction as loud as that of a cabinet phonograph with a bighorn and of' better tonal quality. A diaphragm of that size can behoused in a cylindrical box not more than 2O or 21 inches across. F orsmaller and lighter machines of less volume, a 10- inch or 12-inchdiaphra m is sufficient and only one stage of ampli cation need beprovided for. A machine like that shown in the drawings can be housed ina carrying case about the size ofarwomans hat-box. Of course, the caseneed not be cylindrical, ut may be square, or rectangular, or of anyother practical shape and design. Also, the case containing themechanism may be constructed as part of a large household cabinet. v

Portable mechanical phonographs of the horn type, even the mostexpensive makes,

are incapable of giving a reproduction of good volume and quality,mainly because the small carrying case affords no room for an adequatehorn or amplifying chamber. In the electric phonograph of my inventionas applied to portable machines, a hornless loudspeaking diaphragmis-mounted horizontally at the bottom of a small box, and electricamplifying mechanism is housed in a shallow chamber below themotor-board, thereby producing a phonograph of hand-baggage size andweight, and yet a machine capable of' great volume and fine quality ofre roduction. hitherto unobtainable in ortabIe phonographs. The easewith whic the volume of re reduction may be electrically regulated in te phonogra. h of my invention adds to its practical use ulness. As faras I know, I am the first to provide an electric phonograph of thertable type, and I therefore claim certain features of my invention in afundamental Way.

I claim as my invention:

1. A iortable. electric phonograph comprising, 1n combination, a 'carringcase having a base and a topboard, saidcase being pf less height thanlength or width, whereby said case is portable, means to provide anupper compartment below the topboard and la. lower compartment above thebase, said lower'compartment forming a sound chamber freely o en tothe'outer air, a 'loud-speaking djap ra m mounted horizontally in saidsound cham r, electromagnetic means for operating said diaphragm, anelectric reproducer loa operatively mounted over the topboard forplaying records, and electric apparatus in said upper compartment foramplifying the electric impulses of said re roducer and 'transmittingthem to said diap ragm operating means.

2. In a liornless electric phonograph, an outer casing having a topboard and a base, a loudspeaking diaphragm 'mountedin horizontalposition on said`base, said casing being open around the diaphragm for`the passage of sound intoA the outer'air, a unit in said casing foroperating said diaphragm, an electric reproducer operatively mountedover the topA board `for playing records, `electric devices supported inthe space between the top board and the diaphragm, and connectionswhereby said devices constitute a system for amplifying the electricimpulses ol said reproducer and transmitting them to said unit.

3. An electric phonograph comprising, in combinatioma casing providedwith a top board and a motor-driven turntable, a loud-v housed in saidcompartment and so connecty ed as' to constitute a self-contained systeml'ior transmitting the electric impulses of said .said reproducer tosaid unit.

et. `lin an electric phonograph, an outer casing providedwith a topboard and with an inner transverse partition whichdivides the casinginto an upper compartment and a lower compartment, saidupper,compartment between the top board and thepartition beingpractically closed,`a door for the lower compartment to open the same'trrtlie outer air, said door when closed forming part et the outercasing structure, a loudspeaking diaphragm mounted in the lowercompartment, an electromagnetic unit-in'said casing for operating saiddiaphragm, said partition being adapted todeflectsound waves coming fromthe diaphragm into the outer air vand said door being adjustable in openposition to deflect sound waves into the desired direction, an electricreproducer operatively mounted over said top board, and electric devicessupported in said upper compartment and so connected as to constitute asystem for transmitting the electric impulses of said reproducer to saidunit.

An electric phonograph comprising, -in

combination, a casing provided with a top board and a motor-driventurntable, .a cone diaphragm mounted -horizontally at the bottom of saidCasin with the apex of the cone pointing upward y, the casing aroundsaid diaphragm being open to the outer air for the passage of soundwaves, a conc-shaped pai'- tition arranged transversely in said casingbetweenithe top board and said iliaphragn'i with the apex of thepartit-ion pointing downwardy ly toward thevdiaphragm, whereby saidpar-v tition'acts to deflect sound waves coming froin thel diaphragminto the outer air, anelcctromagnetic unit in said casing for operatingsaid diaphragm, an electric reproducer opera- 30 tively mounted oversaid top board for playing a record on the turntable, and electricdevices supported in the compartment between said top board andpartition for transmitting the electric impulses of sa-id'repros?.

ducer to said unit. v

.6. In an electric phonograph, an outer casing having a topboard and abase, a loudspeaking diaphragm mounted on said base,`

said casing being open around the diaphragm ooor the passage of soundintothe outer air, a unit in said casing for operating said dia'-phragm, anl electric'reproducer operatively mounted over the top boardfor playing records, electric devices supported in the space board andthe diaphragm for between the to lie electric impulses of saidretransmitting t producer to said unit, and means arrangedv4 in saidcasing between said devices and said diaphragm for deflecting soundAwaves into 1 the outer air. l

7. A portable self-contained electric phon ograph comprising an outercasing having a top board and a base, an electric reproducer operativelymounted over said top board, a v

lioriiless loudspeaking diaphragm mounted horizontally on said base, anelectromagnetic unit for operating said diaphragm, a transversepartition in saidcasingbetween the top board and said diaphragm, saidtop board and partition forming a practically closed compartment, andmeans in said compartment for transmitting the electric impulses of saidreproducerto said unit.

8. A portable self-contained electric phonograph comprising a norlnallyclosed outer case or box having three compartments, an upper or lidcompartmenthousing an electric reproducer above the top board and havingmeans for supporting a stack of records with 12 out interference by saidreproducer, a bottom compartment eontai nin g a hornless loud-v speakingdiaphragm and having one or more doors to open and close the space abovethe diaphragm, an electromagnetic unit for op-` erating said diaphragm,and an intermediate compartment directly below the top board forcontaining electric devices adapted tof form a self-contained-system fortransmit-l nu ting the-electric impulses of said reproducer to saidunit.

9. In an electric phonograph, an outer casing having a top boardand abase, a loudspeaking diaphragm mounted on said base, said casing beingopen around the diaphragm for the passage of sound into the outer air, aunit in said casing for operating said diaphragm, an electric reproduceroperatively mounted over the top board for playing records, a pluralityof separate chambers or re- A cesses extending below the top board andopen at the top for access, a cover for each of said chambers adjustablymounted on the top board for opening and closing the chamber below, anelectric device mounted in each chamber independently of the otherdevices, and means for so connecting said devices that they constitute asystem for transmitting the electric impulses of said reproducer to saidunit.

10. An electric phonograph comprising an outer casing having a top boardand a base, lan electric re reducer operatively mounted over said topcard, a hornless louds eaking diaphragm mounted horizontally in tliespace between the top board and said base, an electromagnetic unit foroperating said diaphragm, multi-stage mechanism in said cabinet foramplifying the electric impulses of said reproducer and transmittingthem to said unit, and a hand-operable switch in said cabinet forcontrolling the number of stages 4 of amplification of said transmittingmechamsm.'l i 1 11. In an electric phonograph, a cabinet having achamber for the passage of sound into the outer air, a door for closingand opening said chamber, electric re reducing mechanism in saidcabinet, sai cluding a lurality of amplifying tubes, a switch in tliefilament circuits of said tubes adapted to be opened and closed by saiddoor when the latter is closed and opened, and a separate hand-operatedswitch for selectively `connecting one or more tubes in circuit, saidswitches being connected in series in the filament circuit of each tube.y

12. In an electric phonograph, a cabinet having a top board, electricreproducer mechanism in said cabinet, said mechanism including atransformer, a support for said transformerbelow the top board,saidvsupport being accessible through an opening in the top board, meansenga ng said transformer for automatically hol ing it in predeterminedposition upon insertion thereofthrough said opening into said support,means' for automatically connecting said transformer in circuit when thesame is properly positioned in said support, and a movable cover -forsaid cpenin mounted on the top board.

13. n an electric phonograph, an outer casing having a top board and abase, a loudspeaking diaphragm mounted on Said base,

mechanism insaid casing being open around the diaphragm fonthepassage of.sound 4into 'the outer air, a unit -in.-said -casing for operating saiddiaphragm, airelectric reproducer operatively mounted-overthe topboardfor playing records, electricdevices supported in thfe l spiace betweentheftop boardand thevdiap ragm' for* transmitting the electric-impulsesof' said-reproducer-v to said unit, said devices including plurality.-ofA amplifying tubes, switch mechanism -in saidcasing-for selectivelyconnecting one ormoref of said tubes for operatiomand means oroperatingsaid switch mechanism-- v s 1:1'

14. In an electric-phonograph,- a cabinet having a top board anda base,-a cone diaphragm mounted on said base, ,there being a space between thediaphragm and the base, an electromagnetic unit fixed on said base insaid space and operatively connected to said diaphragm. said base andthe-parts mounted thereon being attachable to and removable 15. Anelectric phonograph comprising, in

combination, a casing provided with a to board and a motor-driventurntable, a lou speaking diaphragm mounted horizontally at the bottomof said casing, a transverse` partition arranged in said casing betweensaid top boa-rd and said diaphragm, said top board andpartition forminga practically closed compartment, the space or chamber between saidpartition and said diaphragm being o n to the outer air, an electromaetic unit 1n said casing for operating sai diaphragm, said partitionbeing adapted to deflect sound waves coming from said diaphragm into theouter air, an electric reproducer operatively mount-ed over said topboard for playing records on the turntable, electric devices supportedin said compartment Afor transmitting the electric impulses of saidreproducer to said unit. said devices including a plurality ofamplifying tubes, switch mechanism in said compartment for selectivelyconnecting one or more of said tubes for operation, and a fin er pieceon the top board for operating said switch mechanlsm.

16. A portable self-contained electric phonograph comprising, incombination, a substantially cylindrical outer casingl provided with alid and with a supporting stand-A producer to said unit.

at one side, a top board at the upper end of said ca sin and atransverse partition within the casing to form a closed compartmentbelow the top board, a plurality of openings arranged radially in thetop board, said openings lying practically in that .half of the topboard which extends toward said stand, a movable cover on the top boardfor each opening, a plurality of supports in said comartment arranged inline with said openings, an electric device carried by each support,said devices being insertable and remov-v able through said openingswithout disturbing the top board, the arrangement of said devices beingsuch that their weight serves to stabilize the casing when resting onits stand, a hornless loudspeaking diaphragm mounted at the' bottom' ofsaid casing, one or more doors on said casing for closing and openingthe chamber above said diaphragm, an electromagnetic unit in said casingfor operating said diaphragm, an electric reproducer operatively mountedover the top board, and Vconnections whereby said electric devicesconstitute a self-contained system for transmitting the electricimpulses of said re- 17. In an electric phonograph, an outer casingprovided with a top board and with an inner transverse partition whichdivides the casing into an upper compartment and a lower compartment,said upper compartment betweenthe top board and-the partition beingpractically closed, a door for the lower compartment to open the samevto the outer air, a l'oudspeaking diaphragm mounted in the lowercompartment, an electroma etic unit in said casing for operating saidiaphragm, said partition being adapted to defleet sound waves comingfrom the diaphragm into the outer air and said door being adjustable inopen position to deflect sound waves into the desired direction, anelectric reproducer operatively mounted over said top board, velectricdevices supported in said upper compartment for transmitting theelectric impulses of said reproducer to said unit, said devicesincluding an amplifying tube, and means controlled by said door wherebythe filament circuit of said tube is automatically opened when the dooris closed and whereby said circuit is automaticallyclosed` when the dooris opened.

18. In an electric phonograph, an outer casing provided with a top boardand with an inner transverse partition which divides the casing into anupper compartment and a lower compartment, said upper compartmentbetween the top board and the partition being practically closed, a doorfor ythe lower compartment to open the same to the outer air, aloudspeaking diaphragm mounted inthe lower compartment, anelectromagnetic unit in said casingfor operating said diaphragm, saidpartition being adapted tov switch mechanism, and a switch controlled bysaid door for opening the filament circuits of vsaid tubes when the dooris closed and closing said circuits when the door is opened.

19. An electric phonograph comprising a cabinet having a top board and abase, a loudspeaking diaphragm mounted on said base, an electromagneticunit for operating said diaphragm, a transverse partition between saidtop board and diaphragm `to form a practically closed compartment, adoor for opening the casing around said diaphragm for the passage ofsound into Ithe outer air,

said door when closed' forming part of the outer casing structure, anelectric reproducer operatively mounted over said top board, electricdevices mounted in said closed chamvber below the top board which isprovided with openings to permit ready access to said' devices, movablecovers for normally closing said openings, means for so connecting said'devices that they constitute a system for transmitting the electricimpulses of said reproducer to said unit, a switch in said system, andmeans operated by said door for holding said switch open as long as thedoor remains closed, said last-named means automatically closing saidswitch when the door is opened.

. 20. A portable self-contained electric phonograph comprising anormally closed outer box which consists o a body part and a hollow lid,a top board at the upper end of said body part and a base at the otherend thereiio of, a motor-driven turntable supported over the top board,a hornless loudspeaking diaphragm mounted on said base and ofsubstantially the same size as the base, an electromagnetic unit foroperating saiddiaphragm, a transverse partition between saidA top boardand diaphragm to form a practically closed.

chamber, a door for opening the casing around said diaphragm for thepassage of sound into the outer air, said door when closed forming partof the outer casing struc-` ture, an arm mounted on the top board to.swing horizontally over a record on the turntable, an electricreproducer carried by said arm, means for holding said arm in rest posi-'tion away from the turntable, electric devices mounted in said closedChambenmeans for so connecting said devices that they constitute 13ovment below said section for receiving electric apparatus operativelyconnected with said reproducer, said section forming a movable .coverfor said compartment. and a loudspeaking diaphragm mounted in said caseand having an electromagnetic driving unit connected with saidapparatus.

22. A hornless electric phonograph comprising an outer casing having atopboard and a base, means to provide a closed compartment below saidtopboard, the space between said compartment and said base providing asound chamber open to the outer air, a loudspeakingI diaphragm mountedhorizontallv in said chamber, a driving unit for said diaphragm. anelectric reproducer operatively mounted over the topboard 4for playingrecords, and electric devices supported in said closed compartment fortransmitting the electric impulses of said reproducer to said drivingunit.

23. A hornless electric phonograph comprising an outer casing having atopboard and a base, means to provide a closed compartment below saidtopboard, the space between said compartment and said base providing asound chamber open to the outer air, a cone diaphragm mountedhorizontally in said chamber, a driving unit for said diaphragm, anelectric reproducer operatively mounted over the topboard for playingrecords, electric devices supported in said closed compartment fortransmitting the electric impulses of said reproducer to said drivingunit, and a conical board arranged horizontally in said casing oppositesaid diap hragm to deflect sound waves into the open a1r.

24. In an electric phonograph, a cabinet having a to board and a chamberbelow said top board or the passage of sound into the outer air, a'doorfor opening and closing said chamber, electric reproducingmechanismincluding an ampliym tube with a filament circuit, a pair of switc esconnected in series in said filament circuit, means whereb one of saidswitches is opened and closed y said door when the latter is closed ando ned, and hand-operable means carried by t e cabinet for actuating theother switch.

25. In a hornless electric phonograph, an outer casing havin atop boardan a ase, a

`loudspeaking disp agm mounted in horiice iis

